Embodiments of the invention relate to a non-invasive medical imaging technique, such as magnetic resonance elastography (“MRE”), used to measure stiffness of tissues.
Current MRE technology, including systems that employ an acoustic driver or a purely pneumatic driver system, are generally limited to low frequency vibrations (e.g., 100 Hz or less). Because the wavelengths from the low frequency vibrations are smaller than the dimensions of some tissues, current pneumatic systems can be used to generate stable stiffness maps for some organs such as the liver, which might then be used to diagnose liver diseases, such as liver fibrosis. These limitations similarly affect the ability to use MRE technologies to generate stable stiffness maps for organs such as the heart, prostate, pancreas, spleen, eye, etc.